Tuning-fork.



A. F. DIXON.

TUNING FORK.

APPLICATION FILED AUG. 30. I916.

NEH

lm en for: Amos F Dixon.

Affy

. UNITED STATES PATENT OFFICE.

AMOS F. DIXON, OF NEWARK, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC GOM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TUNING-FORK.

Specification of Letters Patent.

Patented Feb. 26, 1918.

Application filed August 30, 1918. Serial No. 117,651.

To all whom it may concern:

Be it known that I, AMos F. DIXON, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Tuning- Forks, of which the following is a full, clear, concise, and exact description.

This invention relates to electromechanical vibrators, and more particularly to means for readily and accurately altering or adjusting the rate of Vibration of devices of this character.

It is well known that the period of vibration of tuning forks and reeds may be varied by changing the effective length or the distribution of the vibrating masses. The first of these methods has been readily accomplished by providing an adjustable stop such as disclosed in Figure 2 of Patent No. 1,185,712, dated J une 6, 1916, and it has been the usual practice to provide for the other method of adjustment by placing a slidable weight upon each of the tines. It is highly desirable that the period of vibration be capable of adjustment while the fork is in action, and while the first of the hereinbefore-mentioned methods exhibits this advantageous feature, it has been found that the performance of the fork is not as dependable, minute, as when the shifting weight is employed.

Heretofore the shifting weight method has been open to the objection that the fork must be stopped in order to make any change in adjustment. This causes delays in the operation of the mechanism or system under control, and consequentlyresults in loss in time efficiency. When this device is used in connection with multiplex telegraph systems, this feature is especially serious and objectionable in cases of heavy line trafiic on account of line loss, delays in the transmission of messages and waste of operators time. Another objectionable feature is the difficulty encountered in adjusting-the two weights individually to exactly correspond ing positions on the tines.

The object of this invention is to provide a fork possessed of the most dependable, minute and accurate adjustment and at the same time free from the above-mentioned objectionable feature, and to this end the invention relates to the provision of means for allowing the distribution of the vibrator the possible changes in speed so method ing masses to be varied at will without arresting the vibratory action, thereby permitting continuous uninterrupted action of the mechanism or system controlled thereby. Means are also provided for imparting a uniform movement simultaneously to the two weights, thereby maintaining at all times a fixed relation between them.

The above and other objects of this invention will be fully set forth in the following description and claims, and will be readily understood by reference to the accompanying drawing, wherein Fig. l is a plan view of the preferred embodiment; Fig. 2 is a side elevation of a portion of the structure shown in Fig. 1; and Fig. 3 is a cross-sectional view on line 3--3 of Fig. 2.

It will be readily understood that the tines of the fork described herein may be struck to set them in vibration, and may be maintained in vibration by means of an electromagnet acting on each tine in a well-known manner. Since it is old in the art to employ electromagnetic means for maintaining the vibration of tuning forks, and since it forms no part of this invention, it is neither described herein nor shown in the drawing.

The tuning fork and. auxiliary parts are mounted on a base 10 which may be of any suitable material for forming a rigid support. The tuning fork is carried by a bracket 12 which is securely fixed to the base 10. Carried by each tine of the fork is an adjustable weight 14, adapted to be easily slid backward or forward along the tine as desired for the purpose of controlling the frequency of vibration of the tines. A spring 16 is carried on the inside of each weight and is adapted to press against the tine to prevent the weight from rattling while the fork is in service. Each weight is pivotally connected by an arm or link 18 to a post 20, mounted on a movable member or block 22. The movable member or block 22 is adapted to rest on the upwardly extending portion 24; of the base 10 and to be slid along on this upwardly projecting portion by means of a threaded screw or re 26 which is supported at one end by the bracket 12 and at the other end by a member 28. The member 28 is secured to one end of the upwardly extending portion 2i. The links 18 are li ht and are pivotally connected to the weights 1% and also to the post 20 so as not to interfere with the vibration of lhe tuning fork tines. The lhllzs 18 are,

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